Clamshell



FIG. 1 is a top perspective view of a clamshell, showing my new design;

FIG. 2 is a bottom perspective view thereof;

FIG. 3 is a side elevational view thereof, with the opposite side being a mirror image thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a rear view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof. 

The ornamental design for a clamshell, as shown and described. 